1. Field of the Invention
The present invention relates to an optical reader, or more particularly, to a compact bar-code reader applicable to portable use.
In recent years, information input using bar codes has prevailed. For example, when a shopper purchases a product at a store, a bar-code reader is used to read a bar code carried by the product. Thus, the product code provided in the form of the bar code can be input and the purchase can be registered.
For controlling inventories in a warehouse, it has become a matter of daily practice to read bar codes carried by the inventory or by containers for the inventory and to carry out inventory control on the basis of the read data.
Thus, the bar-code reader is employed in information input for a variety of applications. Bar-code readers of optimal forms (shapes or the like) are used for the respective applications. The present invention realizes a bar-code reader usable for various kinds of applications.
2. Description of the Related Art
Conventional bar-code readers are broadly divided by application into stationary readers and portable (hand-held) readers.
The stationary reader is literally a reader placed on, for example, a cashier's counter or a conveyer for carrying articles. The stationary reader has a read window. Scanning light such as laser light is emitted through the read window. The scanning light emitted through the read window is irradiated to an article bearing a bar code. The surface of the article is scanned by the scanning light. The scanning light scanned over the article is reflected. The reflected light is received through the read window, whereby the bar code is read. An article that is an object of bar-code reading passes a position at a distance from the reader.
The orientations of bar codes passing in front of the reader are not always a constant direction but are usually various directions (inclinations). A general stationary reader therefore produces scanning light so as to generate a scanning pattern created by scanning rays traveling in a plurality of directions, in particular, a scanning pattern created by mutually-intersecting scanning rays.
A light reception sensor for receiving light reflected from a bar code is incorporated in the stationary reader, light reflected from a bar-code surface is scattered light. A condenser for gathering as much of the light reflected from a bar code as possible is therefore placed in front of the light reception sensor.
As mentioned above, the stationary reader is designed to read bar codes of articles passing a position away from the reader. The focal position of scanning light emitted through the read window is therefore set to a position away from the read window.
In the case of the stationary reader; a user is required to merely pass articles in front of the read window. Bar codes are then read out. Scanning for bar-code reading is very simple. Maneuverability is excellent. In particular, even when it is required to read bar codes carried by a large number of articles for a limited period of time, since the articles need merely be passed in front of the reader, bar-code reading can be achieved efficiently.
The hand-held reader is a reader which is held in a hand and of which the read window is directed toward articles in order to read bar codes carried by the articles.
In the case of the stationary reader, since articles must be passed in front of the read window, when an article, for example, a heavy article or large article is hard to pass the read window, the maneuver for reading is hard to do. In case an article contains liquid or an article cannot be tilted, it is conceivable that the article may be passed in front of the read window but the bar-code surface thereof may not be able to be directed toward the read window.
In contrast, a hand-held reader is designed to approach an article for reading. Even if an article bearing a bar code is large or heavy, the bar code can be read readily. Even when an article cannot be tilted, a bar code can be read by bringing the reader to the position of the bar code.
Herein, a gun-shaped reader has, similarly to the stationary reader, a form suitable for reading the bar code of an article located relatively distant. The gun reader has a grip by which a user grasps and operates the reader.
In the case of the gun reader, a user holds the grip and directs a read window thereof toward a bar code to be read. A laser light source is lit by manipulating a trigger switch formed on the grip. A scanning beam is then emitted through the read window, whereby the bar code is read out.
Unlike the aforesaid readers, a touch-system reader is a reader that is brought into contact with a bar code for reading or that is used to read a bar code located very near. A light source such as an LED and a light reception sensor such as a CCD are incorporated in the touch reader. For reading a bar code, a light source illuminates the bar-code surface. Light reflected from the bar code is then received by the light reception sensor.
There is a method to be adopted when bar codes cannot be affixed directly to products or the like, wherein: a plurality of bar codes are recorded on a menu sheet in order to create a so-called bar-code menu; and when it is required to input product information, a necessary bar code is read out. Numerous different bar codes are recorded mutually adjacent on the bar-code menu. When an attempt is made to read the bar-code menu, only the bar code to be read must be read by the reader but unwanted bar codes must not be read thereby.
However, in the case of the stationary reader or the like, scanning rays to be scanned in a plurality of directions (or sometimes mutually-intersecting scanning rays) are emitted. The scan range covered by the stationary reader is very wide. When this kind of reader is used to scan a bar-code menu, the possibility of scanning and reading unnecessary bar codes is very high. It is quite hard to scan only a specific bar code. Moreover, for reading a bar-code menu using the gun reader, a method in which the reader is distant from or near to the bar-code menu is conceivable. In this case, when the gun reader is located at a distant position, it is hard to align a bar code with a position scanned by the reader. When the gun reader is too close, the read window interferes with locating the position being scanned. When an attempt is made to read a bar-code menu using either the stationary or gun reader, bar codes that need not to be read are read out. These readers are therefore unsuitable for reading the bar-code menu.
By contrast, the touch reader is brought into contact with a bar code or located at a position very close to the bar code. A very limited range alone is an object range of reading. The touch reader can easily read specific bar codes alone selectively and is therefore very suitable for reading a bar-code menu.
As mentioned above, readers associated with bar-code read forms have been used in the past. The readers may be suitable for certain applications but may not be suitable for other applications. The readers are applicable to only specific applications. For coping with various read forms, readers associated with the read forms must be prepared.
For example, as mentioned above, it is difficult for the stationary reader to read bar codes borne by articles that are difficult to pass in front of the read window; such as, heavy articles. When the bar codes borne by such articles must be read, the hand-held reader must be made ready to operate.
By contrast, in the case of the hand-held reader, it is required to direct the reader toward a bar code. Especially, in the case of the touch reader, the reader must approach a bar code to such an extent that it comes into contact with the bar code. The maneuverability for reading is poor. When numerous bar codes must be read in a short period of time, the use of the stationary reader is essential to improvement of reading efficiency.
Furthermore, since the stationary reader and gun reader scan a wide range, there is a possibility of reading excessive bar codes. The stationary reader and gun reader are therefore unsuitable for reading a bar-code menu. Especially, in the case of the gun reader, when the reader is too close to a menu sheet, a bar code is hidden behind the face of the reader. It becomes hard to locate a position of the menu sheet being scanned or to check if a bar code that is an object of reading is being scanned successfully.
When there is a possibility of reading a bar-code menu, the use of the touch reader is needed. However, the touch reader cannot read a bar code located at a distance.
Consequently, optimal readers must be prepared for various read forms. However, preparing two or three kinds of readers for different read forms leads to an increase in cost involved in installing equipment. Besides, the case in which the use frequencies of readers dedicated to different applications are the same is rarer than the case in which the use frequencies of some of the readers dedicated to specific applications are higher. There is difficulty even cost-wise in preparing readers, which operate in rarely-used forms, just in case.
For preparing readers that operate in a plurality of forms, an extra space is needed to install the plurality of readers. However, only a limited space can be allocated to, for example, a cashier's counter. When a store itself is narrow, it cannot afford to install the plurality of readers. In this case, the idea of installing the plurality of readers itself becomes a disadvantageous condition for the store.